The objectives of this study are 1) to investigate the clinical efficacy of GS4104 in patients with influenza; 2) to investigate the antiviral efficacy of GS4104 in patients with influenza; 3) investigate the safety and tolerability of GS4104 in patients with influenza; 4) determine the kinetics of GS4071 following oral administration of GS4104; 5) to investigate the impact of treatment of acute disease on the use of medical and non-medical resources associated with influenza.